The problem with this trend and prediction is that it doesn't address what's actually inside the bottle. With tequila there is at least the perceived notion that the raw ingredients are expensive and aging further ups the price. With vodka, consumers have been hearing for years that every brand is the most pure, distilled the most times, and tastes the best. It's become meaningless, so now marketers are turning to expensive designer bottles and rap star endorsements, furthering the distance between what's inside and outside the bottle.
Vodka brand development is about setting a price point, then creating a marketing package to justify it. This isn't new- Grey Goose was designed to be made in France just because France sounded better- but now the once-expensive premium brands like Absolut and Stoli are developing their own ultra-premium offshoots just to be competitively priced with newer more expensive brands.
And it's not like the vodka is getting much better.
What I am starting to find interesting is the backlash: Because all marketing is focussed onward and upward without changing what's inward, there is now room for clever brands to sneak into the cracks with different approaches. Already, the Sobieski brand is counter-marketing with their "Truth in Vodka" campaign advertising that $12 vodka is just as good as as $30 brands. I would guess that additional backlash campaigns will advertise vodkas that have "flavor, not just style" (you can pay me for that later), as well as focusing more on ingredients. I think the brand Karlsson's is smart for advertising seven kinds of "virgin" potatoes, though I haven't tried the product yet.
It's strange that vodka is such a huge seller and incredibly popular, but most everybody spends more time discussing the marketing of the product rather than the product itself.